You can force the ImageIO Tools not to use the native libraries by starting a program with this switch:

-Dcom.sun.media.imageio.disableCodecLib=true

At one time, the following was true (according to jgarnet):

If use of native code is disallowed then the JPEG and PNG reader-writer plug-ins and some accelerations used for bilevel TIFF compression will not be available nor will the native implementation of the JPEG 2000 reader-writer plug-in; the Java implementation of the JPEG 2000 plug-in will however be available. The respective plug-ins will detect that native libraries cannot be used and respond accordingly.